激光衍射粒径测量中的Chin-Shifrin反演算法

Chin-Shifrin inversion algorithm for measuring of particle size distribution by laser diffraction method

建立了以线阵CCD作为探测组件的激光衍射粒径测量系统用于颗粒群直径分布的测量。在数值计算的基础上,分析了传统Chin-Shifrin积分变换粒径分布反演算法存在的两个问题:小粒径反演结果的发散和多假峰现象,并结合理论分析给出了这两种现象的物理图像。提出了修正积分变换公式以解决小粒径反演结果发散的问题并针对Chin-Shifrin变换的具体应用,通过对比散射光强角分布特征,研究了Fraunhofer衍射对Mie散射近似的有效角度范围。计算结果显示,最大近似角度是随着粒径参数上升单调下降的,但积分变换的精度是不断提高的。最后,应用改进的Chin-Shifrin反演算法处理了实验测量数据,结果表明,改进的反演算法的精度较高,适合工业领域的应用。

By using a linear CCD as the detector module,a measuring system for particle size distribution was established by laser diffraction.Based on numerical computation,the two problems in Chin-Shifrin integration particle size inversion algorithm：the divergence of inversion in a small particle size and its false peaks,were analyzed and the causes of these phenomena were explained.Then,the modification of the integration formula was proposed to resolve the divergence problem.Aiming at the particular application on Chin-Shifrin integral transform,the effective angle range of Fraunhofer diffraction approximation to Mie scattering was studied by comparing the pattern of Mie scattering and that of Fraunhofer diffraction.The numerical result show that the valid angle for diffraction approximation decreases as the angle becomes large,but the precision of the inversion has increased.Finally,this improved Chin-Shifrin inversion algorithm was used to process experimental data.The experimental result shows that the improved inversion algorithm has high precision and is suitable for applications in industry.